Tim "Timbaland" Mosley, the most in-demand music producer in the world, is tired. But the task of staying awake is made easier because, right now, Mosley is doing something he really enjoys: talking about how great he is.

"I don't think about other people," he says, with supreme diffidence when asked which other producers he might compare himself to. "If I did, I'd wanna compete. But I don't think like that, because I'm above everybody. My music is on a whole 'nother level. I'm up here," he says, grinning, his left hand waving around high above his head. "And everyone else," his left hand scrapes the floor, "is over there."

It's hard work being the world's pre-eminent rap music producer, particularly when the tracks you make - skittish, minimal, at once supremely commercial and creatively cutting edge - are both popular and credible. It means everyone wants a piece of you: not just rappers, but pop stars, rock stars, even movie stars.

Since he made his name building backing tracks for R&B singer Aaliyah, and in his widely acclaimed partnership with his high school friend, rapper Missy Elliott, Timbaland has been one of hip-hop's most adventurous manipulators of sound and melody. According to the online resource, the All Music Guide, he has produced, remixed or appeared on records by at least 82 different artists, although this list is likely to be incomplete.

If Mosley has a fault, it is not a lack of confidence. Half an hour in his company would convince even the most hardened sceptic that, at least in his own head, 34-year-old Timbaland is the single greatest creative force currently active in popular music. It would be easy to laugh at such arrogance - were it not for the fact that, by most of the available means of measurement, he is probably right.

And the Timbaland empire is growing. He has added to the state-of-the-art studio he built at his first home in Virginia Beach, Virginia (where he, Elliott and fellow locals the Neptunes have been honoured with a Recording Arts and Sciences Day, inaugurated by the town's mayor), with property in Miami and on the west coast of the US. Today, we have met to talk about his new label, Mosley Music Group, and its first release, Loose, the third album from Canadian singer Nelly Furtado. The record, which he produced most of, entered the US album charts at No 1. Instead, his restless mind is already on to the next thing.

"I don't really like to look back," he shrugs. "I've got a vault full of, like, a thousand reels of music that's never been touched that I've made over the years. I just like to do fresh stuff. Once it's done, it's done."

Making music isn't work, he reckons: at least, it shouldn't be, and it certainly isn't in the case of his most recent and highest-profile release, SexyBack, the new and decidedly odd Justin Timberlake single.

"When you're working with somebody, you're just trying to create something, to see if it does work," he says. "Me and Justin is different: it's not work, it's magic. Magic is when you just don't think about it: you go in there and the magic is so strong and it just comes out. The magic, the combination, is so powerful you don't have to think about it."

Timbaland contributed tracks to Justin's first solo album, Justified, in 2002, and SexyBack, as sparse and uncompromising as it sounds, is clearly the work of two men finding some strange common ground. It is telling that Mosley talks of the art of production in terms of matrimony.

"Good production is like a beautiful marriage," the bachelor says. "It makes a happy home. Think about it: Quincy Jones and Michael Jackson - that was a beautiful marriage. And they shoulda stayed married: Michael lost it after he left Quincy. He coulda got it back. Still could! Michael needs to do what I'm doin' with Justin right now."

Mosley seems to define the term "driven". His relaxation of choice is working out. He attends the New Jerusalem Church of God in Christ when he is in Virginia Beach. Inspiration comes from within - "from the heart, then the head" - and definitely not from listening to the competition.

"I don't really like where music is at right now," he scowls. "It's boring, too watered-down. Nobody's takin' chances. It's all in the box, and the box gets too tight. Somebody's gotta break the box, bust it open. To me, making music is about taking risks. The Justin single is a risk - it's a different record. Some people say they like it, some people don't know. But when you hear it the second time, that's when it starts to hit you. A record like that will stay around longer than a record that hits you right away."

The queue of artists beating a path to Timbaland's studio door is lengthening. Jamie Foxx not only worked with Mosley on his US chart-topping album, Unpredictable, he borrowed the producer's mobile studio so he could finish the record while filming Miami Vice. After Coldplay's Chris Martin turned up at a Nelly Furtado session - he co-wrote All Good Things (Come to An End) with her and Mosley - another collaboration beckoned.

"We did some songs, just playing around in the studio," Mosley says airily of his sessions with Martin. "Just regular stuff." There are no plans, as yet, to release any of these tracks.

He is also working with Björk ("Whoo! The marriage, it's beautiful. You gotta hear it! A lot of people think it's weird her working with me, but I think it's how she sings on top of my beats that make it") and, after some prodding, admits to having begun work with Jay-Z on the supposedly retired rap star's comeback album.

Mosley is full of cocksure bravado, and likes to make out that his music happens without tangible effort. But it is clear nobody could sustain the sort of career he has purely by accident and, in the end, he admits as much.

"You have to socialise," he says, allowing a momentary glimpse at his working process. "You've got to be involved with the energy of the artist, and if they don't have no energy you've got to make it for 'em. It's like being a doctor, you know? You've gotta look after 'em, always be on call, always just understand and learn about them. That's how you produce somebody."

Explicit and irresistible: Timbaland's greatest hits

Ginuwine: Pony from Ginuwine the Bachelor (Sony, 1996)

R&B titans Jodeci introduced 21-year-old Ginuwine to aspirant producer Mosley. Pony was the first track they crafted together, its low-slung slouch featuring what would become the producer's trademark skittering top-end percussion and a lyric that wasn't so much innuendo as explicit. Ginuwine got his deal, and Tim launched his own career.

Aaliyah: Are You That Somebody? single (Universal, 1998)

After helming Aaliyah's second LP, Timbaland created this monstrous hit as part of his soundtrack to the 1998 Eddie Murphy vehicle Dr Dolittle. The lurching beat urges the song along rather than simply providing the singer with a backdrop, while a rap from Timbaland - another incipient trademark - is given prominence. Rock band Maroon 5 rewrote the riff for their Not Coming Home.

In Missy, Tim found his ideal foil - a vocalist as ready to try something different as he was. Perhaps the definitive Timbaland track, Get Ur Freak On still sounds alien and otherworldly. Based around a three-note Indian sitar figure, the only drums are a whoomping bass and the occasional tabla, yet its dynamism is irresistible.

Jay-Z: Hola Hovito from The Blueprint (Def Jam, 2001)

Proving he could also do straightforward hip-hop, this subtly bizarre track was Mosley's sole contribution to Jay-Z's acknowledged masterpiece. Mariachi horns joust with anachronistic analogue synth doodles, while a harp lists through what sounds like the coda of a late 1960s funk track, looped back on itself in an uneasy stumble.

Nelly Furtado: All Good Things (Come To An End) from Loose (Mosley Music Group/Geffen, 2006)

Based around a cloud of acoustic guitars and pan pipes, only the jittery drum programming marks this end-of-the-affair rumination as a Timbaland track. Co-written with Furtado and Chris Martin (who also recorded a vocal track, removed after contractual problems), it could signal where his collaboration with the Coldplay frontman might head.

Containing all the trademark Timbaland tics - daringly minimal instrumentation, determinedly abstract sound, vague Eastern influence, a rap from the producer - SexyBack is certainly, as Mosley maintains, "a risk". The jury is still out on Emperor Timberlake's new clothes, but his tailor seems very pleased with himself.

· Nelly Furtado's single Promiscuous produced by Timbaland, is out on September 4; the album Loose is out now. Justin Timberlake's single SexyBack is out on August 21.